if I have passed my class 12th with pcm from bihar board in 2015 and I want to give biology exam as a single subject from nios will my bihar board 12th marksheet lose its validity
Hope you are all fine. With reference to your question, if you have passed your 12th with PCM (Physics-Chemistry-Mathematics) from Bihar Board and you want to give biology exam as a single subject from NIOS, your Bihar Board 12th marksheet will not lose its validity
However, if you are planning this to write your NEET, do note that at the time of document verification certain colleges might not accept it.
Hope this helps.